1. Field of the Invention
The invention relates to apparatus for producing ozone from oxygen.
2. Description of the Art
From German Laying-Open Specification 37 31 168, an apparatus for producing ozone from oxygen has become known which has two electrodes separated by a dielectric in the form of a tube and having a high conductivity. The discharge electrode, therewith, is constructed as a discrete structural element and tightly bears on the circumference of the dielectric. The discharge electrode, around which the oxygen flows, forms a non-closed surface and is in the form of a wire. By applying an electric field, a discharge is triggered in the gas space surrounding the discharge electrode and on the dielectric which is made of a ceramic material. By means of this apparatus, with which ozone is produced in accordance with the principle of silent electric discharge, high production densities per unit of area are attained with a discharge of medium frequency as compared to other arrangements. Since an "open" electrode in the form of a wire is used, direct cooling is possible. The electrode wire is made of high-grade steel, nickel or copper. It is true that the production of ozone by means of the known apparatus enables high production densities per unit of an area to be achieved with an operation of medium frequency, but energy yield and the attainable production density per unit of area, with high concentrations, are limited and, in part, inferior to comparable results of ozone-producing apparatus of a conventional kind in which the arrangement is made up of the combination of electrode-dielectric-air gap-dielectric.
To the technical use of an ozone-producing apparatus, energy yield is of great importance. In addition, more recent applications of ozone necessitate particularly high ozone concentrations. The semiconductor industry shall serve as a relevant example. There, ozone is increasingly used for cleansing processes and as a process gas and, therefore, the availability of high ozone concentrations not only leads to an acceleration of the cleansing processes; but, also, to qualitative improvements, e.g., of precipitated SiO.sub.2 -coatings.
It, therefore, is the object of the present invention to provide an apparatus for producing ozone from oxygen in which energy yield and production density per unit of area, with high concentrations, are improved.